feat: add platform-specific initialization handling

- iOS: Use EventChannel-based signaling from native layer
- Android/other platforms: Use direct initialization with null check
- Add isInitialized flag in AppDelegate to handle late subscriptions
- Add debug logging for initialization events

Author: denischilik

example/ios/Runner/AppDelegate.swift

@@ -5,6 +5,8 @@ import mParticle_Apple_SDK
 @main
 @objc class AppDelegate: FlutterAppDelegate, FlutterStreamHandler {
   private var eventSink: FlutterEventSink?
+    
+  var isInitialized = false
 
   override func application(
     _ application: UIApplication,
@@ -28,7 +30,7 @@ import mParticle_Apple_SDK
       object: nil
     )
 
-    let options = MParticleOptions(key: "api-key", secret: "secret")
+    let options = MParticleOptions(key: "us1-773c44ed5daf6840a65b75832b548be1", secret: "Mqsh_nuVFbffg10jROjoRR2GudqY4t6rZ5ogQcgLBB-v1nL3kUabEEF6we5JOCmr")
     options.logLevel = MPILogLevel.verbose
     MParticle.sharedInstance().start(with: options)
 
@@ -39,6 +41,9 @@ import mParticle_Apple_SDK
 
   func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
     self.eventSink = events
+    if isInitialized {
+      events(["initialized": true])
+    }
     return nil
   }
 
@@ -50,6 +55,7 @@ import mParticle_Apple_SDK
   // MARK: - mParticle Initialization
 
   @objc private func handleMParticleInitialized(notification: Notification) {
+    isInitialized = true
     if let eventSink = self.eventSink {
       eventSink(["initialized": true])
     }

example/lib/main.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
@@ -76,18 +77,29 @@ class _MyAppState extends State<MyApp> {
 
   // Platform messages are asynchronous, so we initialize in an async method.
   Future<void> initMparticle() async {
-    // Subscribe to mParticle initialization events from native code
-    _initializationSubscription = _initializationEventChannel
-        .receiveBroadcastStream()
-        .listen((event) {
-      if (event is Map && event['initialized'] == true) {
+    if (Platform.isIOS) {
+      // iOS: Subscribe to mParticle initialization events from native code
+      _initializationSubscription = _initializationEventChannel
+          .receiveBroadcastStream()
+          .listen((event) async {
+        if (event is Map && event['initialized'] == true) {
+          print("mParticle initialized from native layer");
+          mpInstance = await MparticleFlutterSdk.getInstance();
+          setState(() {
+            _isInitialized = true;
+          });
+        }
+      });
+    } else {
+      // Android and other platforms: Use original initialization
+      mpInstance = await MparticleFlutterSdk.getInstance();
+      
+      if (mpInstance != null) {
         setState(() {
           _isInitialized = true;
         });
       }
-    });
-    
-    mpInstance = await MparticleFlutterSdk.getInstance();
+    }
   }
 
   void identityCallbackSuccess(IdentityApiResult successResponse) {